What is a DMA?

And what areas does a DMA include?

A DMA is a “Designated Market Area” — each DMA is a geographical area where Nielsen measures media consumption, ranked by local television homes. A DMA not only includes the urban center and suburbs, but it also includes the surrounding counties (aka trade area) where small towns and rural homes receive the same television signals. There are 210 DMAs in the United States. New York City is the largest DMA, and Glendive, MT is the smallest DMA.